This Center has been in existence and very active for over 20 years. During the past funding period (1991-1995) the training of about 20 pre- and post-Ph.D. students and clinical fellows has occurred via the Center activities. The Center participants have been productive with the publication of over 60 scientific articles and reviews. Many new advances in the field have occurred during the past funding period. This Center renewal application proposes the continuation of five projects that focus on novel aspects of the mechanism of action of reproductive hormones and the regulation of reproductive processes. Two projects concern the progesterone receptor and the mechanism of progestin action on gene expression; two projects concern androgen-induced genes and gene products; and one project relates to receptors and the mechanism of gonadotropin action. These projects represent new extensions of our existing center program. Dr. D. O. Toft serves as Director and Dr. T. C. Spelsberg as Co- Director. The order of th projects in this renewal application is as follows: Project 1 Dr. Spelsberg Chromatin acceptor sites for progesterone Project 2 Dr. Toft Isolation and characterization of progesterone receptor Project 3 Dr. Tindall Characterization of early growth response genes in prostate cells Project 4 Dr. Roche Structure and function studies of gonadotropin receptor